In producing petroleum and other useful fluids from production wells, it is generally known to provide a submersible pumping system, such as an electric submersible pumping system (ESP), for raising the fluids collected in a well. Typically, production fluids enter a wellbore via perforations made in a well casing adjacent a production formation. Fluids contained in the formation collect in the wellbore and may be raised by the pumping system to a collection point above the earth's surface. The ESP systems can also be used to move the fluid from one zone to another.
An ESP system is generally comprised of a motor section, a pump section, and a protector. Current motor designs require clean oil, not only to minimize magnetic losses, but also to provide appropriate lubrication in the hydrodynamic bearings that support the rotor. Contamination of the clean oil leads to short circuit which is one of the most common failure modes in electric motors used in ESP applications.
The protector of a typical ESP system provides an elaborate seal intended to maintain the clean oil environment separate from the well fluid. One end of the protector is open to the well bore, while the other end is connected to the interior of the motor. Existing protectors have the common purpose of forming a barrier between the motor oil and the well fluid. Circumstances such as thermal cycling, mechanical seal failures, wear, or scale can result in a malfunction of the protector. Such malfunction allows well fluid to reach the motor resulting in an electrical short circuit.